Body Fat Calculator

Body Fat Calculator

Body fat percentage is a more accurate indicator of health than weight alone. This calculator uses the US Navy Method, which is widely used by fitness professionals and military organizations.

Key Terms

  • Body Fat Percentage — The proportion of your body weight that is fat tissue.
  • Lean Body Mass — Everything in your body that isn't fat (muscles, bones, organs).
  • Essential Fat — The minimum amount of fat needed for normal bodily function.
  • US Navy Method — A formula using height, waist, and neck measurements to estimate body fat.

US Navy Method Formula

Men: %BF = 495 / (1.0324 - 0.19077 × log(waist-neck) + 0.15456 × log(height)) - 450
Women: %BF = 495 / (1.29579 - 0.35004 × log(waist+hip-neck) + 0.22100 × log(height)) - 450

Body Fat Categories (Men)

  • 2-5% — Essential fat (minimum for health)
  • 6-13% — Athletes
  • 14-17% — Fitness
  • 18-24% — Average
  • 25%+ — Obese

Body Fat Categories (Women)

  • 10-13% — Essential fat
  • 14-20% — Athletes
  • 21-24% — Fitness
  • 25-31% — Average
  • 32%+ — Obese

Tips for Measuring

  • Measure waist at the narrowest point (usually at the navel).
  • Measure neck below the larynx with tape sloping downward.
  • Take measurements in the morning before eating.
  • Use a non-stretch tape measure for accuracy.
  • Track trends over time rather than single measurements.